Process for modifying keratin fibers



United States Patent 3,477,805 PROCESS FOR MODIFYING KERATIN FIBERSDmitry M. Gagarine and Emile E. Habib, Spartauhurg, and Kermit S. LaFleur, Clemson, S.C., assignors to Deering Milliken ResearchCorporation, Spartauburg, S.C., a corporation of Delaware No Drawing.Continuation of application Ser. No. 111,447, May 22, 1961. Thisapplication Aug. 6, 1965, Ser. No. 477,958

Int. Cl. D06m 3/06, 3/08, 3/12 US. Cl. 8-128 12 Claims This inventionrelates to a novel process for modifying the characteristics of woolfabrics and, more particularly, to a process for imparting to woolfabrics a propensity for a permanent finish and/or pleat.

This application is a continuation of application Ser. No. 111,447,filed May 22, 1961, now abandoned.

Methods of improving the finish of wool fabrics have been the subject ofconsiderable research efforts in recent years. The luster, hand andtexture of W001 fabrics is normally enhanced by either one or twomethods, that is, by adding up to about by weight of mohair to the woolfabric and decating the fabric or by a process known as London shrinking(or paper pressing), which involves relaxing the fabric in water andthen pressing for protracted periods of time. Both methods providefabrics having satisfactory luster, hand, and texture, though atincreased cost. Unfortunately, however, these desirable characteristicsare not permanent and are removed by the garment manufacturer during hissponging operation, during which the fabric is relaxed in water prior tocutting.

To date, therefore, no satisfactory process has been developed forproviding, at the mill level, a wool fabric having a lustrous finishpermanent to subsequent treat-- ments by the garment manufacturer.

Many procedures are available for imparting to wool fabrics a creasewhich is fairly resistant to distortion even after considerable wear andwetting. All of these procedures, however, have proven sufficientlyunsatisfactory as to have attained only limited success. For example,one such process involves spraying the finished garment, for example, apair of trousers, with a solution of a reducing agent immediately beforepressing. It is necessary in this process that the amount of waterapplied to the fabric be at least by weight of the fabric. This processnecessarily involves spray equipment, manual labor and a multiplicity ofdiscontinuous steps and manipulations. In ad dition, this process isapplicable only to the finished garment, since there are short andlimiting time factors in the process between application of the reducingagent and press-finishing of the cloth.

These problems have been partially overcome by a process wherein thereducing agent is applied at the mill level followed by drying attemperatures necessarily below C. so as to inhibit the activity of thereducing agent on the wool fibers. This low temperature drying, however,is highly objectionable in a mill operation in that this procedurerequires far more space and time than is economically desirableFurthermore, even though the reducing agent is applied at the milllevel, the consumer must moisten the fabric to a moisture content of atleast about 40% by weight prior to pressing, again adding materially tothe equipment and labor involved in producing the fabric.

In still another process, monoethanolamine bisulfite is applied to thefabric at the mill level and dried in the conventional manner. However,in order for the consumer to obtain any permanent shaping of thisfabric, it is necessary to steam the fabric for 20 minutes under highpressure prior to pressing. This, of course, is time consuming andexpensive and is objected to by the consumer.

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There has been developed to date, therefore, no satisfactory andeconomical process, which may be done at the mill level, for impartingto a fabric a propensity for permanent creasing, thereby reducing costsand hazards involved in subsequent treatments by the consumer.

The difficulties inherent in the processes of the prior art are obviatedin accordance with this invention which comprises treating the fabricwith a reducing agent and from about 3 to about 50%, by weight of thefabric, of a swelling agent. The fabric so treated may then be shippedto garment manufacturers, processed into garments and pressed underlower moisture levels than hitherto considered possible to obtain pleatspermanent to subsequent manipulation and wetting. For example, garmentsprepared from the novel fabric of this invention may be pressed on aHoffman press (30 seconds" steam-pressing, 30 seconds drypressing),without additional treatment such as wetting to high moisture levels ofabout 40% by weight, to obtain permanent pleats. Preferably, the fabricis shipped at moisture levels of less than about 30% by weight andpressed under the same initial conditions. Particularly in instanceswhere the fabric contains relatively small amounts of moisture, e.g.,about 3 to 10% by weight, additional moisture may be absorbed from thesteam during the preferred steaming procedure, so that actual moisturelevels in the fabric during pressing will be slightly higher than at theoutset of pressing. This moisture increase is accomplished, however,without cumbersome, uneconomcial spraying techniques as are normallyrequired.

If desired, the luster of the fabric so treated may be improved prior toshipping in a press-finishing operation involving contacting at leastone surface of the fabric with a pressing element under conditionssufficient only to provide a lustrous fabric surface.

A highly lustrous fabric may be obtained by semi-decating orfull-decating the chemically modified fabric particularly when thedecating procedure is combined with the press-finishing operation,although these decating procedures substantially remove the propensityin the fabric for subsequent permanent pleating.

To impart only a permanent finish to the fabric while retaining in thefabric its propensity for permanent pleating, it is essential that thefinishing step be carefully controlled so that the fibers at or near thesurface of the fabric are affected by the treatment so as to provide apermanent finish, while a sufiicient number of the remaining fibersthroughout the fabric are not sufiiciently affected so as to destroytheir propensity for accepting a permanent pleat. Generally, the desiredcondition is provided by controlling the temperature and pressure of thepressing element and the time of exposure of the fabric to the element.Generally, these conditions vary with the amount of reagents and waterremaining in the fabric. For example, if unrcacted reducing agent ispresent in the fabric at the time of pressfinishing, the total period ofexposure of the fabric to the pressing conditions should be morelimited. Since the temperature of the preferred finishing means, aconventional rotary press, is maintained at about 260 F., the period ofexposure may be decreased by increasing the feed rate of the fabricthrough the press, e.g., in excess of about 30 yards per minute. In.instances where the unrcacted reducing agent has been removed bywashing, reduced feed rates are suitable, for example, about 20 yardsper minute.

Obviously, a sufficient number of passes must be made to insure that thedesired fabric properties are produced, although one pass is generallysutlicient once the desired conditions have been established. Thepressure on these rolls may be increased so that higher luster may beobtained, although care must be taken to insure retention of the fabricspropensity for subsequent permanent pleating by the" garment maker.

The press-finishing operation is improved by steaming the fabricbriefly, prior to or concurrently with, the pressing operation. Thissteaming operation is particularly desirable where the treated fabric isessentially dry, i.e., containing less than about 5% moisture by weightprior to press-finishing. The period of exposure of the fabric to thesteam depends to a large extent on the steam pressure and feed rate ofthe fabric. Pretreatment of a fabric traveling at a rate of about 25yards per minute with steam at about pounds per square inch, forexample, is entirely suitable. Steaming for extended periods of time,for example, in excess of about seconds is wholly unnecessary foroptimum operation of this invention.

Selection of the press-finishing element depends largely on the typefinish desired. For example, finishes approaching a shine may beobtained by using a pressing element having a solid planar surface. Morelustrous finishes are obtained when the pressing element surface ismoderately irregular, as in a slightly knurled surface. For purposes ofthe present invention, this latter surface is preferred. Texturedfinishes are provided when fabric-faced pressing elements are utilized,while embossed finishes may be obtained by using embossing rolls of thedesired construction.

Furthermore, the decating procedures described hereinafter are entirelysatisfactory in themselves for the production of highly desirablefinishes.

If the permanent pleating propensity is not particularly desired by theconsumer, it may be readily removed by a decating process which,coincidentally, considerably improves the luster and hand of the fabricover that obtained after rotary pressing. This procedure is preferablyconducted by wrapping the finished fabric with a smooth surfacedmaterial, such as a cotton or rayon fabric, in such a manner that thesmooth surface contacts the treated fabric at its finished surface. If anonlustrous or matte finish is desired, the liner used in the decatingshould have a coarse textured surface. The resulting wrap is decated bytreatment in an autoclave for at least about 2 minutes with steam at apressure of at least about pounds per square inch. After this treatment,the fabric is cooled and dried by vacuum in the conventional manner.This decating process removes the propensity of the fabric for permanentpleating to a substantial degree and should not be used where permanentpleating is desired by the consumer.

On the other hand, if the optimum permanent pleating propensity isdesired, the press-finishing operation may be eliminated or at leastconducted under mild conditions, e.g., short periods of time atrelatively low temperatures, such as with the rotary press rolls atabout room temperature. The fabric so produced may be pressed,preferably in the presence of steam, by the garment manufacturer underthe normal low moisture levels available with standard pressingequipment. Obviously, thegarment manufacturer may press at a highermoisture level, e.g., in excess of 40% by weight, and obtain permanentpleats, but an advantage of this invention is that this uneconomicalprocedure is eliminated.

The reducing agent and swelling agent may be applied to the fabric inany desired amount, depending upon the degree of reducing desired. Ingeneral, optimum results are obtained when from about 0.01 to about 10%by weight of the reducing agent and from about 3 to about 50% by weightof the swelling agent are applied to the fabric. Most preferably, fromabout 1 to about 3% by weight of the reducing agent and from about 7.5to about 15% by Weight of the swelling agent are applied to the fabric.

While the effect of the reducing agent may be subject to somespeculation amongst wool experts, it is generally considered that thereducing agent ruptures a plurality of the cystine disulfide linkagespresent in the wool fibers.

The concentration of the reducing agent and the period of exposure ofthe wool fabric to the reducing agent should be controlled so thatexcessive ruptures of these linkages, resulting in excessive degradationof the fabric, is not permitted to occur. Generally, it is believed thatexcessive degradation occurs when an excessive number of the cystinedisulfide linkages of the wool fiber are ruptured. Extreme cases ofdegradation may be checked visually, in that the wool fiber appears tobecome gelatinous in nature when an extremely excessive number of thecystine disulfide linkages are ruptured. In any case, the degree ofdegradation may be detected by physical tests.

A satisfactory level of disulfide linkage reduction is indicated whenthe fabric treated with the reducing agent satisfactorily passesthe'following test:

1) Remove reducing agent in fabric by washing in water 75 F. and squeezeto a wet pickup of (2) Fold the fabric upon itself and press the foldedarea with a hand iron set at 370 F. for 1 minute under a pressure offour pounds per square inch; and

(3) Immerse the dry, pressed fabric in Water at F. for 30 minutes. Afterremoval from this water and drying, a fairly sharp pleat should beretained.

Any reducing agent capable of rupturing the desired level of thedisulfide linkages is suitable for use in accordance with thisinvention. Among the suitable reducing agents there are includedmetallic formaldehyde sulfoxylates, such as zinc formaldehydesulfoxylate, the alkali metal sulfoxylates, such as sodium formaldehydesulfoxylate; alkali metal borohydrides, such as sodium borohydride,potassium borohydride and sodium potassium borohydride; alkali metalsulfites, such as sodium or potassium bisulfite, sulfite, metabisulfite,or hydrosulfite, ammonium bisulfite, sodium sulfide, sodiumhydrosulfide, cystine hydrochloride, sodium hypophosphite; sodiumthiosulfate; sodium dithionate; titanous chloride; sulfurous acid;mercaptan acids, such as thioglycolic acid and its water-soluble salts,such as sodium, potassium or ammonium thioglycolate; mercaptans, such ashydrogen sulfide, and sodium or potassium hydrosulfide; alkylmercaptans, such as butyl or ethyl mercaptans and mercaptan glycols,such as fi-mercapto ethanol; and mixtures of these reducing agents.

Of these reducing agents, those containing sodium bisulfite,particularly the sodium bisulfite-sodium sulfite (50/50) combinations,are most highly desired for optimum rupturing of the disulfide linkageswithin a short period of time at minimal cost. j

While it is known that the swelling agents for the wool swell the woolfibers and possibly assist in the reduction of the disulfide linkages,there appears to be no ready explanation for why this swelling actionprovides the advantages that occur in its use. For example, when areducing agent is utilized alone, it is necessary to dry the fabric atlow temperatures for extended periods of time to avoid destroying thepropensity of the treated fabric to be permanently pleated. When thesame fabric, however, is treated with a reducing agent in combinationwith a swelling agent, it is possible to dry the fabric at a much highertemperature and to a greater degree without destroying this propensity,thereby greatly facilitating the mill drying operation. For example, thefabric treated in this manner may be dried at temperatuers approaching200 F. to moisture contents as low as 3%, whereas a similar treatmentwould remove a substantial amount of the permanent pleating propensitiesof a fabric treated only with a reducing agent.

Similarly, there is no obvious explanation for the fact that a fabrictreated with both a reducing agentand a swelling agent may be pressed atlow moisture levels (for example, less than about 20% moisture) toobtain a permanent pleat, even after extended aging periods, as opposedto conventional procedures which require prolonged presteaming (e.g.,about 20 minutes) or spraying to obtain a water content of at least 40%by weight in the fabric prior to pressing.

Urea constitutes the most readily available and desirable swellingagent, although any other material which will swell wool fibers in anaqueous medium is suitable. For example, guanadine compounds such as thehydrochloride; formamide, N,N-dirnethyl formamide, acetamide, thiourea,phenol, lithium salts, such as the chloride, bromide, and iodide and thelike are similarly useful.

The reducing agent and swelling agent may be added to the fabricin anydesired sequence, but in a preferred embodiment, the reagents are addedto the fabric by impregnating with an aqueous solution containing bothreducing agent and swelling agent in the desired proportions. The fabricmay then be immediately removed from the solution, squeezed to thedesired wet pick-up and allowed to age for an appropriate time beforefurther processing, in accordance with this invention. Generally, noadvantage is obtained by aging the impregnated fabric for more than twohours, although aging times in excess of 24 hours have been utilizedwith success. Alternatively, the fabric may be aged while immersed inthe reagent bath. r

. Good results may be obtained by treating with reducing agent-swellingagent solutions at a pH between about 3 and about 10, although optimumresults are obtained at pH levels between about 4.5 and about 7.0.

In addition, the temperature of the treating solutions may be adjustedto any desired level. For example, room temperature solutions areentirely satisfactory, although these solutions may be heated where itis desired to limit the exposure time of the fabric to the solution orwhere it is desired to utilize low concentrations of the reactants, forexample, the fabric need not be exposed to a heated solution of thereducing agent and swelling agent for more than about 2 minutes toobtain optimum results, while longer periods of exposure, e.g., at leastabout 15 minutes, are preferred when the fabric is padded with thetreating solution at room temperature.

Permanent luster and/or pleats are most easily attained when thepress-finishing procedure at the mill level and/ or pressing by thegarment manufacturer is conducted while the fabric still contains thereducing agent and swelling agent.

Long periods of exposure to the wide variety of conditions that a fabricin storage is subjected to, however, may make it desirable to reduce thelevel of leachable reagents in the fabric, particularly with respect tothe reducing agent. Consequently, it is preferred to treat the fabricwith the reducing agent, wash the fabric and then apply the swellingagent. A fabric treated in this manner can withstand more rigorousstorage conditions while retaining the highly desirable propensity forsubsequent permanent pleating by the garment manufacturer. In thisregard, it appears critical that at'least 3% by weight of the swellingagent must be present in the fabric at the time of pressing in order toobtain permanent pleats at the desired low moisture levels.

In a particularly preferred embodiment of this invention, the fabric isimpregnated with an aqueous solution containing the reducing agent, agedfor an appropriate time, e.g., from about 30 minutes to about 2 hours,after which the fabric is passed through water, preferably at about 75F. This treated fabric is then impregnated with an aqueous solution ofthe swelling agent, dried and prepared for shipment to garmentmanufacturers, in the desired condition, i.e., with or without treatmentfor per-'- manent luster.

The mill level drying prior to press-finishing, as for example on arotary press, may be effected at room temperature if desired, but oneadvantage of this invention is that the treated fabric may be dried atelevated temperatures, i.e., up to about 200 F., without destroying thefabrics ability to accept subsequently a permanent finish and pleat.Normal mill drying temperatures of 170 to about 180 F. are, therefore,entirely suitable for this drying operation, thereby presenting adistinct advantage over prior art procedures which require lowtemperature drying in order to retain in the fabric a propensity forsubsequent permanent finishing and pleating.

While the process of this invention is particularly adapted to fabricscomposed essentially of keratin fibers, particularly those composedentirely of wood fibers, it is also applicable to fabrics whereinsynthetic or natural fibers are blended with the wool components and toblends of keratin fibers, such as mohair, alpaca, cashmere, vicuna,guanaco, camels hair, silk, llama and the like. The preferred syntheticfibers include polyamides, such as polyhexamethylene adipamide;polyesters, such as polyethylene terephthalate; and acrylic fibers, suchas acrylonitrile homopolymers or copolymers containing at least aboutcombined acrylonitrile, such as acrylonitrile/methacrylate (85/15), andcellulosics, such as cellulose acetate and viscose rayon. Of the naturalfibers which may be blended with the keratin fibers, cotton ispreferred.

The process of this invention may be performed on woven, non-woven, orknitted fabrics of any type, dyed or undyed provided, of course, thatthe dyes are stable to the reagents. The low temperature treatments withthe reducing agent are particularly adapted to the treament of dyedgoods. Conversely, the high temperature treatments may not be entirelysuitable for treatment of dyed goods since, at these elevatedtemperatures, the reducing agent may, in some instances, strip some dyesfrom the fabric.

- The following examples illustrate preferred embodiments of the presentinvention:

EXAMPLE I A wool fabric, composed of 55 ends of 2 ply 40 worsted countyarn (Z16 and S15 twist in the plies), and 46 picks of 2 ply 40 worstedcount yarn (Z16 and S15 twist in the plies) is padded with a solution inwater at F. (pH of 4.4) containing 2% sodium bisulfite and 10% urea with0.02% of the nonionic wetting agent Surfonic N-95. The fabric issqueezed out to obtain a 100% wet pickup of the solution on the fabric.The fabric is then laid out on a pallet, folded over upon itself,covered with a film of polyethylene and aged for 30 minutes at roomtemperature. After Washing in water at about 75 F. for about /2 minute,the fabric is then dried down to about 5% moisture at a temperature ofabout 175 F. V

The fabric is then passed through a jet of steam into a David GessnerCo. rotary press model No. 20 (Serial PD506) at about 25-30 yards perminute, the press rolls being heated to a temperature of about 275 F.

To illustrate the permanence of the luster obtained, a swatch of thefabric so treated and an untreated control fabric which has beensimilarly rotary pressed are immersed in water containing 0.05% byweight of Synowet HR (an anionic wetting agent) at F. for 10 minutes.The finish and luster of the treated fabric is substantially equivalentto the excellent qualities obtained at the rotary press, while theuntreated fabric loses substantially all its finish and luster.

A second swatch of the treated fabric and an untreated fabric swatch arefolded over and steam pressed for 30 seconds and dry pressed for anadditional 30 seconds in a standard Hoffman press. After boiling inwater containing 0.05% by weight of Surfonic N-95, the treated fabricretains substantially its pleated configuration while the untreatedswatch loses its pleat completely.

EXAMPLE II The procedure of Example I is followed except that afterpassing through the rotary press, the fabric is wrapped in a smoothcotton liner and treated with steam at 20 pounds per square inchpressure for 2 minutes in an autoclave, after which the steaming isterminated and the fabric is dried under vacuum for about 8 minutes. Theresulting fabric has a more lustrous finish and better hand than thefabric of Example I, but is not characterized by a propensity forsubstantially permanent pleating.

EXAMPLE III The procedure of Example I is followed except that thefabric is aged for 2 hours at room temperature after padding with thebisulfite-urea solution. A similarly lustrous fabric is provided afterpassing the fabric so aged through a rotary press at a rate of 25 yardsper minute. The finish and pleats obtained by this procedure are similarto the results of Example I.

EXAMPLE IV The fabric of Example I is padded with a solution in water of2% sodium bisulfite and 10% urea at 100 F. (pH of 4.4) with a wet pickupof about 100%. The fabric is then folded onto a pallet undersubstantially tensionless conditions and covered with a sheet ofpolyethylene to inhibit drying. The fabric is permitted to stand in thiscondition at room temperature (about 80 F.) for 100 minutes. The agedfabric is then crabbed by passing at a rate of about 10 yards per minutethrough 4 tanks of water at a temperature of about 75 F. The fabric isthen dried to about 3.5% moisture content in a dryer containing hot airat a temperature of 172 F. The fabric is press-finished as in Example Ito obtain a similarly permanent finish. The fabric is then shelf-agedfor 7 days at room temperature. Similarly shelf-permanent pleats areformed in this fabric by pressing as in Example I.

EXAMPLE V The procedure of Example IV is repeated except that thewashing procedure is conducted after the fabric is passed through therotary press. A similarly permanent finish is imparted to the fabricwhen it is passed through the rotary press at about 5 yards per minute.After washing, the fabric is dried again as in Example IV to a moisturecontent of about 4% by weight and pressed in a Hoffman press, wherebysimilarly permanent pleats are obtained.

EXAMPLE VI The procedure of Example IV is repeated except that thefabric is wrapped in a smooth cotton liner after it is passed throughthe rotary press and the wrapped fabric is decated for 2 minutes atpounds per square inch pressure of steam in an autoclave after which itis vacuum dried for 8 minutes. The crease obtained under the Hoffmanpress is not permanent when the fabric is decated in this manner,although the lustrous fabric finish is retained throughout all of theseoperations.

EXAMPLE VII The procedure of Example IV is repeated except that thetreating solution is replaced with the following solutions:

Good results are obtained as in Example IV with each of these solutions,although slightly better results are obtained with the NaHSO /Na SOcombinations.

EXAMPLE VIII The procedure of Example VII is repeated except thatinstead of impregnating the fabric swatches with the treating solutionby padding them through the solutions and aging, the fabrics are keptimmersed in the various solutions for periods of 15 minutes, 30 minutes,1, 2 and 4 hours and not aged after removal. Each of the solutions ismaintained at room temperature. Similarly permanent finishes areobtained in each of the treated fabrics" by passing them through therotary press at higher rates proportional to the period of contact ofthe fabric with the solution.

EXAMPLE IX The fabric of Example I is impregnated with a 2% by Weightsolution of sodium bisulfite, squeezed to a wet pickup of laid out on apallet and aged, under a film of polyethylene, for 30 minutes at roomtemperature. After washing with water at 75 F., the fabric is passedthree times through a 12% aqueous solution of urea to pick up 10% byweight of the urea on the fabric. The fabric is then passed through atenter frame and dried in the conventional manner. This fabric isshipped to a garment manufacturer, who prepares from the fabric severalpairs of mens trousers. The pleats formed in these fabrics by standardHoffman pressing procedures (30 seconds steaming, 30 secondsdry-pressing) are retained after immersion in water at F. for 30minutes.

That which is claimed is:

1. A process for modifying the characteristics of a fabric comprisingkeratin fibers including the steps of (l) treating said fabric with areducing agent capable of rupturing the cystine disulfide linkages inthe keratin fibers and from about 3 to about 50% by weight of a swellingagent; (2) drying said fabric at an elevated temperature to a moisturelevel of less than about 30% by weight, said swelling agent beingsubstantially retained in said fabric; and (3) pressing said fabric at amoisture level of less than about 30% by weight, to set a configurationtherein which is substantially durable to subsequent wear and wetting.

2. A process for modifying the characteristics of a fabric comprisingkeratin fibers including the steps of (1) adding to said fabric areducing agent capable of rupturing the crystine disulfide linkages inthe keratin fibers and from about 3 to about 50% by weight of a swellingagent; (2) drying said fabric at an elevated temperature to a moisturelevel of less than about 30% by weight, said swelling agent beingsubstantially retained in said fabric; and (3) preparing a garment fromsaid fabric and pressing said garment at a moisture level'of less thanabout 30% by weight to impart thereto a pleat capable of withstandingsubsequent wear and wetting without substantial loss of said crease.

3. A process for modifying the characteristics of a fabric comprisingkeratin fibers including the steps of (1) adding to said fabric areducing agent capable of rupturing the cystine disulfide linkages inthe keratin fibers; (2) washing said fabric after permitting asufficient time for the reducing agent to react with the keratin fibers;(3) adding to said washed fabric from about 3 to about 50% by weight ofa swelling agent; (4) drying said fabric at a temperature between 122and 200 F. to a moisture level of less than about 30% by weight, saidswelling agent being substantially retained in said fabric and preparinga garment therefrom; (5) pressing said garment at a moisture level ofless than about 30% by weight to impart thereto a pleat capable ofwithstanding subsequent wear and wetting without substantial loss ofsaid crease. I I

4. The process of claim 3 wherein the garment is steamed and pressed ata moisture level of less than about 30% by weight.

5. A process for modifying the characteristics of a fabric keratinfibers including the steps of (1) treating said fabric with from about0.01 to about 10% by weight of a reducing agent capable of rupturing thecystine disulfide linkages in the keratin fibers and from about 3 toabout 50% by weight of a swelling agent; (2) drying said fabric at anelevated temperature to a moisture content of less than about 30% byweight, said swelling agent being substantially retained in said fabric;(3) contacting at least one surface of said fabric at a moisture levelof less than about 30% by weight with a pressing element underconditions whereby the fibers at or near the surface of said fabric aredurably set in a pressed configuration while a sufficient number of theremaining fibers throughout the fabric are not sufficiently set as todestroy their propensity for subsequent durable setting to provide alustrous fabric surface capable of withstanding manipulation and wettingwithout substantial loss of said luster, said fabric being characterizedby a propensity for subsequent permanent pleating.

6. A process for modifying the characteristics of a fabric composedessentially of keratin fibers comprising the steps of (1) impregnatingsaid fabric with an aqueous solution containing from about 0.01 to about10% by weight of a reducing agent capable of rupturing the cystinedisulfide linkages in the keratin fibers and from about 3 to about 50%by weight of a swelling agent; (2) drying the fabric to a moisturecontent below at least about 20% by weight, said swelling agent beingsubstantially retained in said fabric; (3) contacting at least onesurface of said fabric with a pressing element under conditionssufficient to provide a lustrous fabric capable of withstandingmanipulation and Wetting without substantial loss of said luster; (4)washing said fabric with an aqueous medium; (5) wrapping said fabricwith a porous, flexible material; (6) heating said wrapped fabric andflexible material in the presence of steam at a pressure of at leastabout pounds per square inch; and (7) after terminating the steaming,drying said fabric under vacuum to provide a fabric finish capable ofwithstanding manipulation and wetting without substantial loss thereof.

7. A process for modifying the characteristics of a fabric composedessentially of wool fibers comprising the steps of (1) impregnating saidfabric with an aqueous solution containing from about 1 to about 5% byweight of sodium bisulfite; (2) aging said impregnated fabric for aperiod from about 30 minutes to about 2 hours; (3) Washing said fabricin an aqueous medium; (4) impregnating said fabric with an aqueousmedium containing from about 3 to about by weight of urea; and (5)drying said fabric at a temperature between 122 degrees and 200 degreesB, said fabric thereby being characterized by a propensity forsubsequent durable setting.

8. A wool fabric treated in accordance with claim 5. 9. A wool fabrictreated in accordance with claim 7. 10. The process of claim 1 whereinsaid fabric is dried at a temperature between about 122 and about 200 F.

11. The process of claim 3 wherein the drying procedure of step 4 isconducted at an elevated temperature. 12. The process of claim 1 whereinthe fabric is pressed without the addition of moisture in excess of theregain level prior to pressing.

UNITED STATES PATENTS References Cited 2,672,397 3/ 1954 Lundgren 8-1282,983,569 5/1961 Charle 8-127.5 3,098,694 7/1963 Reider 8--128 FOREIGNPATENTS 443,359 2/1936 Great Britain OTHER REFERENCES Speakman, Journalof the Textile Institute, pp. T627- T628 (1958).

Wolfram et al., Journal of the Society of Dyers & Colorists, vol. 76,169-173, March 1960.

MAYER WEINBLATT, Primary Examiner US. Cl. X.R.

mg UNITED sums PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,477,805 mad November 11, 1969 Dmitry M. Gagarine, Emile E. Habib andKermit S. LaFleur It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

In Column 1, line 21, delete "or" and substitute therefor --of--.

In Column 6, line 9, "wood" should read --woo1--; line 27, "treament"should read --treatment--.

In Column 8, line 75, after "fabric" insert --c0mprising--.

SICmED A111) SEALED FEB 2 4 1970 (SEAL) Am mm: x. 50mm. :11. AttestingOffieer OOIInissioner of Patents

1. A PROCESS FOR MODIFYING THE CHARACTERISTICS OF A FABRIC COMPRISINGKERATIN FIBERS INCLUDING THE STEPS OF (1) TREATING SAID FABRIC WITH AREDUCING AGENT CAPABLE OF RUPTURING THE CYSTINE DISULFIDE LINKAGES INTHE KERATIN FIBERS AND FROM ABOUT 3 TO ABOUT 50% BY WEIGHT OF A SWELLINGAGENT; (2) DRYING SAID FABRIC AT AN ELEVATED TEMPERATURE TO A MOISTURELEVEL OF LESS THAN ABOUT 30% BY WEIGHT, SAID SWELLING AGENT BEINGSUBSTANTIALLY RETAINED IN SAID FABRIC; AND (3) PRESSING SAID FABRIC AT AMOISTURE LEVEL OF LESS THAN ABOUT 30% BY WEIGHT, TO SET A CONFIGURATIONTHEREIN WHICH IS SUBSTANTIALLY DURABLE TO SUBSEQUENT WEAR AND WETTING.